Aerial mapping to capture Ireland in high-res aerial photography

11 November 2014

An aerial mapping project is set to ‘photomap’ the whole of Ireland in high-resolution aerial photography and colour infrared imagery

Leicestershire-based aerial mapping specialist Bluesky, the company behind many of the high-resolution images of England and Wales currently used on Google Earth, has recently announced a new flying programme for Ireland.

The aerial survey specialist already has a contract in the UK supplying geographic data, including aerial photography, to central government organisations such as Natural England, the UK Department for Environment, Food and Rural Affairs, the Environment Agency and English Heritage. This contract has set a new standard for the capture of geographic data; moving from the previous five-year update cycle to an improved three-year update programme. Using this expertise and experience, Bluesky recently announced plans to capture high-resolution aerial photography and colour infrared imagery for the whole of the Republic of Ireland.

This new flying programme will see three dedicated survey planes, equipped with the latest Vexcel camera technology, operate out of multiple flying bases including Dublin, Cork, Shannon, Knock and Donegal. This operational flexibility will ensure that pilots are able to maximise flying opportunities, and therefore data capture, taking into account local weather conditions and air traffic control restrictions. Planes will be on standby from April 2015 in order to capture leaf on aerial photography and colour infrared imagery during the summer months.

Operational control will be based at Bluesky’s Irish headquarters in Cork, with a dedicated support team led by Simon Tidmarsh, operations director; “By throwing maximum resources at this project, including equipment and staff, we’re confident we can achieve what we set out to,” he said. “In other words, some 70,000 square kilometres of the most up to date, accurate and single-season aerial photography for the whole of the Republic of Ireland.”

As raw data, somewhere in the region of 20 Terabytes in total, is collected it will be transferred to Bluesky’s data processing facility in Leicestershire. Here, a team of specialists will transform the thousands of individual images into a seamless, map accurate mosaic producing both the aerial photography and colour infrared map layers. In addition to the two image layers, Bluesky will also produce a national Digital Terrain Model and Digital Surface Model.

“We are aiming to launch the first of this next generation of geographic data solutions for Ireland in September 2015,” added Robert Loughran, international sales manager at Bluesky. “This is a hugely important development for the Irish geographic information industry as it represents a major breakthrough not only in the currency of information available, but also the detail of the products on offer. We’re also planning a dedicated online Mapshop for the hugely important market. This will allow for professional users of geographic to view and download site-specific images and data in a matter of minutes.”

Aerial photography and height models

The core products Bluesky will be creating include digital, high-resolution, colour aerial photography. The national coverage will be at a resolution of 25 centimetres with an optimum viewing scale of 1:1,250; sufficient to see building detail, transport infrastructure and other features not present on traditional map layers. Selected urban areas, including Dublin, Cork, Limerick, Galway, Waterford, Drogheda, Dundalk and Wexford, will be available at the higher resolution of 12.5 centimetres, optimum viewing scale of 1:750, where it is possible to see road markings, people and street furniture.

Both aerial photography layers will be available in a range of formats suitable for use in Geographic Information Systems, CAD software and other desktop mapping systems as well as online at the Bluesky Ireland Mapshop.

In addition to the aerial photography, Bluesky will simultaneously capture colour infrared imagery (CIR). Invisible to the human eye and captured using specialist sensors, CIR images provide a unique view of the earth’s surface. CIR imagery is a valuable tool for studies in landform, vegetation, pollution and other effects of human activity of the earth and its environment. For example, leaves of healthy, growing vegetation reflect a high level of the near-infrared wavelength and appear red, while unhealthy or dormant vegetation may appear light red or a light shade of blue green. Water, on the other hand, absorbs near infrared wavelengths making it appear almost black – or, if it contains amounts of suspended particles, as shades of blue.

As well as capturing the two image-based map layers, Bluesky will also create two detailed height models from the stereoscopic (overlapping) photography. Using photogrammetric techniques, Bluesky can extract height measurements from the images to create both Digital Surface Models (DSM), the earth’s surface including buildings and vegetation, and Digital Terrain Models (DSM), the earth’s surface excluding buildings and vegetation.

With resolutions of 2 metre and 5 metre for the DSM and DTM respectively for national coverage, and higher resolutions of 1 metre and 2.5 metres for urban areas, these models are valuable tools for site planning, line of site analysis and project planning. The height models will be available in a range of formats including ASCII XYZ, ARC Grid, GeoTiff and ERDAS Imagine, to name just a few.

Following the creation of these core datasets, Bluesky also hopes to produce a range of derived products. Already available for other locations, these include:

A detailed National Tree Map providing an assessment of tree height and canopy cover,

3D Building Models designed to support building developers, architects and urban planners, and

Other projects may include thermal surveys, night-time photography and air-quality mapping. As the new aerial photography will be in full stereo and captured to mapping standard specifications, it will also be ideal for producing high-scale topographic mapping.

Aerial mapping data in use

Colour-infrared image of Dublin

Aerial photographs help landscape consultants Cooper Partnership achieve planning permission for some of the most high profile and potentially controversial construction projects in the UK. These have included siting of wind turbines, developments on greenbelt land and nuclear power stations.

“Aerial photographs are perfect for desktop assessments and conceptual master planning, as it’s essential that we convey our layouts and designs as clearly as possible showing how they’ll integrate into the existing landscape in the best possible way,” commented Stacie Kaniecki, senior landscape technician at Cooper Partnership.

3D models created from high-resolution aerial photography are also supporting the pioneering use of building information modelling (BIM) on regeneration and construction projects across London. The 3D models accurately place the projects in their real-world multi dimension context; this provides a base for the integration of other project critical data and allows David Miller Architects to effectively manage the project and communicate with stakeholders.

Digital terrain model imagery

“For initial conception and feasibility stage proposals, where a full-scale survey of the site is neither practicable nor cost effective, but 3D information is desired, being able to obtain this level of information from Bluesky is the perfect solution,” commented David McMahon, senior architect at David Miller Architects.

Kent County Council also uses DTM and DSM data in a wide range of application areas including prediction of archaeological sites, support for highways planning works, viewshed analysis of major works – for example, an incinerator at Aylesford and production of ‘walk profiles’ to give ramblers a more accurate representation of difficulty. The Bluesky data also provides context for other types of mapping and will support feasibility studies and public consultations such as a proposed cable-car system in the Dover area.

3D city models are also helping Mott MacDonald deliver safe, sustainable and user-friendly civil infrastructure projects. The highly accurate and detailed models are being used by the worldwide consultancy to give a better understanding of the wind environment around urban infrastructure projects. By creating highly complex engineering models, Mott MacDonald simulates the flow of wind around a site and creates different scenarios based on the project design.

“The Bluesky data is a key ingredient for our computer simulations, in order to understand how the wind moves around any proposed large-scale development site. The framework CAD model based on the Bluesky data lets us explore a range of design options,” explained Dr Don Wu, senior computation fluid dynamics engineer at Mott MacDonald. “It’s essential that new buildings and redevelopments provide a safe and comfortable experience for all users. The Bluesky data helps us look at different options for access and the use of outside space and amenity areas based on the behaviour of the wind.”

Leicestershire-based aerial mapping specialist Bluesky, the company behind many of the high-resolution images of England and Wales currently used on Google Earth, has recently announced a new flying programme for Ireland.
The aerial survey specialist already has a contract in the UK supplying geographic data, including aerial photography, to central...

The views and opinions expressed within articles of the Engineers Journal are those of the authors and do not necessarily reflect the official policy or position of Engineers Ireland and the editor
of the Engineers Journal.